APC AP8861 Manuel D’Utilisation

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Metered Rack PDU User Guide
3
Watchdog Features
Overview
To detect internal problems and recover from unanticipated inputs, the Rack PDU uses internal, system-
wide watchdog mechanisms. When it restarts to recover from an internal problem, a System: 
Warmstart
 event is recorded in the event log.
Network interface watchdog mechanism
The Rack PDU implements internal watchdog mechanisms to protect itself from becoming inaccessible 
over the network. For example, if the Rack PDU does not receive any network traffic for 9.5 minutes 
(either direct traffic, such as SNMP, or broadcast traffic, such as an Address Resolution Protocol [ARP] 
request), it assumes that there is a problem with its network interface and restarts.
Resetting the network timer
To ensure that the Rack PDU does not restart if the network is quiet for 9.5 minutes, the Rack PDU 
attempts to contact the default gateway every 4.5 minutes. If the gateway is present, it responds to the 
Rack PDU, and the response restarts the 9.5-minute timer. If your application does not require or have a 
gateway, specify the IP address of a computer that is running on the network and is on the subnet. The 
network traffic of that computer will restart the 9.5-minute time frequently enough to prevent the Rack 
PDU from restarting.
Network Port Sharing
About the Network Port Sharing Feature
You can use the Network Port Sharing feature to view the status of and configure and manage up to four 
Rack PDUs using only one network connection.  This is made possible by connecting the Rack PDUs via 
the "In" and "Out" ports on the Rack PDU front panel. 
Note: All Rack PDUs in the group must be using the same Rack PDU firmware revision, 5.1.5 or later 
(excluding v6.0.5 EnergyWise), in order to support the Network Port Sharing Feature.
Display ID
The display ID is a number, 1 to 4, used to uniquely identify the Rack PDUs in a group. After two or 
more Rack PDUs are connected to one another in a group, they can be identified on the various 
interfaces by the use of this "Display ID".  This Display ID is viewable on the LCD by selecting the 
Display Settings > Display ID > Show option on the LCD keypad.
Installation Instructions
Connect up to four Rack PDUs. Insert an RJ45 terminator (included) in the unused "In"/"Out" ports on 
each end of the chain.  
Note: Failure to use terminators may cause a loss of communication on the Rack PDUs. 
Note: To reduce the possibility of communication issues, the maximum total length of cabling 
connecting Rack PDUs in a group should not exceed 10 meters. All Rack PDUs in a Network Port 
Sharing group should reside in the same rack enclosure.
Connect the "Network" port of  one of the grouped Rack PDUs to a network hub or switch.  This unit 
will be the "Host" for the Rack PDU group.  A Host is defined as a Rack PDU that is connected to the 
network and is part of a Rack PDU group. Set up network functionality for this Host Rack PDU as 
specified in the Establish Network Settings section.  The Host will automatically discover any "Guest" 
PDUs connected via In/Out ports.  The Rack PDU group is now available via the Host's IP address.